海泡石和可膨胀性石墨对水性超薄膨胀型钢结构防火涂料阻燃性能的影响

Effect of Sepiolite and Expandable Graphite on Thermal Degradation of Water-based Intumescent Flame-retardant Coatings for Steel Structure

摘要:

采用可膨胀性石墨（EG）和海泡石对传统的APP/PER/MEL膨胀型防火涂料体系进行改性，制备了一种新型水性超薄膨胀型防火涂料，并采用防火性能测试装置、热重分析（TGA）、差热重量分析（DTG）及X射线衍射（XRD）等方法对该防火涂料的耐火性能、热降解过程、碳化层结构进行了研究。热分析结果表明，海泡石与EG复合使用，将充分发挥它们的协同作用：EG在较低温度区域能够延缓碳化层的形成，而海泡石则能够在高温区域阻止碳化层氧化分解，并提高成炭率从而达到阻燃的目的。XRD结果显示，复合使用EG和海泡石能够促进碳化层中TiP2O7的形成，在高温阶段保护碳化层不被氧化。当防火涂料中添加3wt%海泡石和2wt%EG，涂层厚度为1mm时，钢材的耐火时间达到72min。

Abstract:

Expandable Graphite (EG) and sepiolite were added to the traditional APP/PER/MEL systems to get a new kind of water-based intumescent flame retardant coatings for steel structure. The effects of EG/ sepiolite on the fireproofing time and char formation of the coatings were investigated by using heat insulation test, thermo gravimetric analysis (TGA), derivative thermogravimetry (DTG) and X-ray diffraction (XRD). The results of TGA and DTG showed that the use of EG and sepiolite together could exert the flame retardant synergy effects: EG could postpone the formation of char layer at quite low temperature zone while sepiolite increased the stability of the residual char at higher temperature. XRD analysis indicated that the performance of anti-oxidation of the coatings was improved by adding EG and sepiolite. In addition, the fireproofing time of the steel structure was up to 72min when the film thickness of the coatings, which contained 3wt% sepiolite and 2%EG, was 1mm.